Merge pull request #18988 from singh264/openj9_issues_18556_for_v0.44.0-release

(0.44) Fix intermittent LogGeneratedClassesTest failures

Author: tajila

jcl/src/java.base/share/classes/openj9/internal/criu/InternalCRIUSupport.java

@@ -231,7 +231,7 @@ private static native void checkpointJVMImpl(String imageDir,
 
 	private static native String[] getRestoreSystemProperites();
 
-	static {
+	private static void initializeUnsafe() {
 		AccessController.doPrivileged((PrivilegedAction<Void>) () -> {
 			try {
 				Field f = Unsafe.class.getDeclaredField("theUnsafe"); //$NON-NLS-1$
@@ -809,6 +809,10 @@ private void registerRestoreEnvVariables() {
 			return;
 		}
 
+		if (unsafe == null) {
+			initializeUnsafe();
+		}
+
 		J9InternalCheckpointHookAPI.registerPostRestoreHook(HookMode.SINGLE_THREAD_MODE, RESTORE_ENVIRONMENT_VARIABLES_PRIORITY,
 				"Restore environment variables via env file: " + envFile, () -> { //$NON-NLS-1$
 					if (!Files.exists(this.envFile)) {